Wireless monitors are commonly used during exercise, athletic competitions, medical tests and other activities. For example, a heart rate monitor can be worn by a user, contacting the user at a suitable location such as the chest or wrist. A chest-worn monitor may detect an electrocardiogram (EKG) signal of the user's heart, each time a heart beat occurs, and transmit a corresponding pulse in a wireless signal to a receiver unit, where the signal is further processed to determine the heart rate. The receiver unit typically includes a display device which displays the heart rate to the user or other person. For example, the receiver unit can be worn on the user's wrist, provided in a console or other unit which is mounted to an exercise device such as a treadmill or bicycle, or provided in a portable or stationary device which is monitored by an athletic trainer, medical personnel or others.
In addition to monitoring of a heart rate, monitors are available for monitoring other bodily actions, such as breathing, or repetitive physical movements which are performed by a user during exercise, such as steps taken while running, or pedal revolutions during bicycling, and so forth. However, when wireless monitors are used in the same location, crosstalk can occur, preventing the receiver unit from accurately determining a rate at which the bodily action is performed. Other noise sources can also prevent the receiver unit from distinguishing the signal from a monitor. To this end, techniques have been developed for encoding additional identifying data onto the wireless signal. However, the existing approaches have drawbacks such as increased cost, power consumption, and complexity and susceptibility to additional sources of electromagnetic interference.